1. Field of the Invention
The present invention relates to a brake system for a vehicle, comprising a hydraulic pressure generating device for outputting a hydraulic pressure corresponding to a braking operation by a vehicle driver and hydraulic pressure operated wheel brakes mounted on wheels so as to be operated based on the hydraulic pressure output from the hydraulic pressure generating device. The brake system includes an electrically operated parking brake drive device which generates an operating force for operating the wheel brakes, or dedicated parking brakes mounted on wheels separately from the wheel brakes, in response to energization thereof, and which can be maintained in an operated state even upon cancellation of the energization while in the operated state. The brake system also includes a controller for controlling the energization of the electrically operated parking brake drive device.
2. Description of the Background Art
Japanese Patent No. 3595249 discloses a brake system for a vehicle in which when the shift position of the vehicle has been set at a parking position, when the vehicle is stopped on a slope, or when a driver manually operates an operating switch, the state of the vehicle is changed to a parking brake state by the operation of electrically operated parking brake drive device.
When the electrically operated parking brake drive device is operated, noise is generated and electric power is consumed by this operation. In the case where the electrically operated parking brake drive device is operated when the vehicle is stopped on a slope as referred to above, the frequency of the operation is increased depending on a preset threshold value for determining whether or not the vehicle is on a slope, resulting in an increase in frequency of generation of the noise and an increase in amount of the consumed electric power, and leading to degradation in durability of the electrically operated parking brake drive device. As a result, the driver needs to change the shift position to the parking position and operate the operating switch, which are inconvenient operations for the driver.